The present invention relates, in general, to devices used for handling semiconductor material, and more particularly, to members for contacting semiconductor material.
Great care must be taken when handling semiconductor material during production, processing and the like. For example, semiconductor material in the form of wafers are typically handled in large quantities as they are processed to form semiconductor devices. During the handling of the wafers, the wafers are subject to breaking due to mishandling by the manufacturing and processing equipment.
Broken wafers is the source of a substantial undesired expense encountered in the course of processing. The wafers themselves are expensive. Additionally, if the wafers are broken during device fabrication, a great deal of value has been added to the wafer. When the wafer breaks due to mishandling by the processing equipment, the present value of the wafers is lost.
Furthermore, broken wafers cause a substantial interruption in the manufacture process. Wafers can break during any stage in the device fabrication process. Often, wafers break inside sophisticated process equipment which may be evacuated and require a clean environment, devoid of any particles. When a wafer breaks the broken wafer must be cleaned out, and any particle contaminants resulting from the break must be removed. The cleaning process results in significant downtime of processing equipment. When the processing equipment which must be shut down is part of an assembly line manufacturing process, the entire manufacturing line stops. The obvious result is a significant negative impact on production capacity.
Modern processes and materials are making even greater demands on material handling assemblies with regard to avoiding breakage. For example, relatively thinner silicon wafers are now being used. Furthermore, gallium arsenide wafers are being used for an increasing number of applications. Gallium arsenide is much more brittle than the conventional standard silicon wafer. Additionally, gallium arsenide distributes heat much more inefficiently than silicon, yet has about 2.5 times the thermal expansion coefficient. Consequently, gallium arsenide is subject to breakage due to the application of heat in a small localized area. Furthermore, gallium arsenide wafers are typically polished on the backside as well as the front. Wafer handling equipment which relied on friction from the backside to avoid sliding and scoring is ineffective. Additionally, processes are employing much higher temperatures and subjecting wafers to various other more aggravating conditions.
The change in processing and materials presents problems with regard to handling wafers and creates an even greater need for semiconductor material handling equipment which avoids breakage. Accordingly, wafer handling equipment, and particularly a semiconductor material contacting member, is needed which overcomes the severe disadvantages presented.